AB0429 EIGHT-MONTH FOLLOW-UP OF THE NON-MEDICAL SWITCH FROM ETANERCEPT BIO-ORIGINATOR TO GP-2015 OR SB4 ETANERCEPT BIOSIMILARS IN PATIENTS WITH CHRONIC INFLAMMATORY ARTHROPATHIES: A MONOCENTRIC OBSERVATIONAL STUDY
Authors: C. Castellani, L. Di Sanzo, G. Bevignani, E. Molteni, G. Sciarra, M. Di Franco, C. Alessandri, V. Riccieri, R. Priori, F. Ceccarelli, F. R. Spinelli, R. Scrivo, F. Conti
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> After the expiration of bio-originators' licenses, the development of less expensive biosimilars has prompted the switch to these drugs. Data on the switch from etanercept (ETA) bio-originators to biosimilars are reassuring [1-2] but still limited. <h3>Objectives</h3> This observational study evaluated the real-life effectiveness of a non-medical switch from ETA bio-originator to GP-2015 or SB4 biosimilars in our cohort of patients with inflammatory chronic arthritis. <h3>Methods</h3> We enrolled consecutive adult patients with rheumatoid arthritis (RA), psoriatic arthritis (PsA), and ankylosing spondylitis (AS) classified according to standard criteria switched from ETA bio-originator to GP-2015 or SB4 biosimilars for administrative/economic reasons. The date of the switch was the baseline (T0). Patients were reassessed after 4 (T4) and 8 months (T8). At T0, T4, and T8, data on demographic and clinical/laboratory features were registered. Patient-reported outcomes (PROs), such as visual analog scale (VAS 0-10) for pain and global assessment (PGA) and functional status by Health Assessment Questionnaire (HAQ) were used, together with disease-specific scores (DAS28-CRP for RA, DAPSA for PsA, ASDAS-CRP and BASDAI for AS). We assessed the same data at the time of early discontinuation for inefficacy (loss or lack of efficacy – LoE or LaE) or adverse events (AEs). <h3>Results</h3> One hundred and twelve patients switched from ETA bio-originator to GP-2015 [45 RA, F:M=33:12, median age 67 years (IQR 24), median disease duration 214 months (IQR 180), median exposure to bio-originator 126 months (IQR 97); 48 PsA, F:M=18:30, median age 59 years (IQR 18), median disease duration 168 months (IQR 120), median exposure to bio-originator 120 months (IQR 96); 19 AS, F:M=7:12, median age 55 years (IQR 16), median disease duration 162 months (IQR 245), median exposure to bio-originator 132 months (IQR 82)]. No differences were found in the clinical and laboratory parameters compared to T0 in RA and PsA, while AS patients showed an improvement of BASDAI at T8 compared to T4 (p=0.0273). Interestingly, at T8 RA patients experienced a worsening in the HAQ (p=0.0313) with respect to T0 (figure 1A) and PsA patients had a worsening of VAS pain compared to T4 (p=0.0371) (figure 1B). Four (8.8%) RA patients discontinued GP-2015 at T4 due to AEs (1 for recurrent infection of upper airways, 1 for injection site reaction, 1 for skin cancer, 1 for breast cancer). One (2%) PsA patient discontinued GP-2015 at T4 due to AE (oral ulcers). Twenty-eight patients switched from ETA bio-originator to SB4 [14 RA, F:M=13:1, median age 63.5 years (IQR 33), median disease duration 144 months (IQR 206), median exposure to bio-originator 84 months (IQR 96); 11 PsA, F:M=6:5, median age 54 years (IQR 12), median disease duration 205 months (IQR 198), median exposure to bio-originator 177 months (IQR 164); 3 AS, F:M=0:3; median age 56 years, median disease duration 210 months, median exposure to bio-originator 120 months]. An improvement of DAPSA at T4 compared to T0 was observed in PsA patients (p=0.0469). At T8, no differences were found compared to T0. One (9%) PsA patient experienced LoE at T4. <h3>Conclusion</h3> Our data indicate that the switch to GP-2015 or SB4 ETA biosimilars from ETA bio-originator does not bear clinical and laboratory differences in patients with chronic arthropathies. The worse outcome in PROs, which we also observed in the adalimumab bio-originator to biosimilar switch (3), does not reflect a worsening of disease activity indexes and could indicate a possible nocebo response. <h3>References</h3> [1] Ditto MC et al. Sci Rep 2020 [2] Jaworski J et al. Arthritis Res Ther 2019 [3] Scrivo R et al. Clin Exp Rheumatol 2022 Data are shown as Tukey boxplots; lines represent the median level with 25<sup>th</sup>-75<sup>th</sup> percentile; dots represent outliers. <h3>Acknowledgements:</h3> NIL. <h3>Disclosure of Interests</h3> None Declared.